نتایج جستجو برای: 23h

تعداد نتایج: 111  

2005
C. Cano-Raya M. D. Fernández-Ramos L. F. Capitán-Vallvey

A disposable sensor has been developed for the measurement of copper(II) concentration in aqueous solution based on a change in the fluorescence of porphyrazine 2,7,12,17-tetra-tert-butyl-5,10,15,20-tetraaza-21H,23H-porphine (TP). The sensor was constructed by spin-coating a polyester support with a PVC solution containing TP, a plasticizer, the chelating agent Zincon and the ion-pairing benzet...

2003
Mohammad Reza Ganjali Mohammad Reza Pourjavid Arash Mouradzadegun Morteza Hosseini Farhang Mizani

A PVC-based membrane electrode for thallium(I) ions based on 1,21,23,25-tetramethyl-2,20: 3,19-dimetheno[H, 2] H, 23H, 25H-bis-[1,3] dioxocino[5,4-i:5',4'-i] benzo [1,2-d: 5.4-d'] bis [1,3] benzodioxocin(II) has been prepared. The electrode displays a linear dynamic range of 1.0 × 10−1-1.0 × 10−5 M, with a Nernstian slope of 59.8 ± 0.2 mV decad−1, and a detection limit 5.0 × 10−6 M. It has a ve...

Journal: :Journal of the American Chemical Society 2002
Yufan He Tao Ye Eric Borguet

The self-assembly of 5,10,15,20-tetra(4-pyridyl)-21H,23H-porphine (TPyP) on Au(111) electrodes was investigated. The adlayer structure was found to depend on the electrode potential. At positive potentials (>0.5V(SCE)), a disordered layer of TPyP is formed on the Au(111) electrode. STM images showed that the disordered molecules are immobile. At negative potentials (-0.2V(SCE)), however, the mo...

2015
Kamila Konopińska Mariusz Pietrzak Radosław Mazur Elżbieta Malinowska

Porphyrins and metalloporphyrins are promising new protein labels that can be detected using multiple techniques; improving the reliability of the analysis and broadening the range of the linear response. Here, we investigate the potential of 5,10,15,20-tetraphenyl-21H,23H-porphyrin (Tpp) as a hybrid protein label. The electrochemical and optical properties of porphyrin conjugated with bovine s...

Journal: :Archiv der Pharmazie 2013
Ahmed A Fadda Rasha E El-Mekawy Ahmed I El-Shafei Harold Freeman

A novel series of mesotetrakis[aryl]-21H,23H-porphyrin derivatives 2a-j was synthesized from the condensation of aldehyde derivatives 1a-j with pyrrole in the presence of p-toluenesulfonic acid. The synthesized porphyrins were considered as a model to study the free radical-induced damage of biological membranes and the protective effects of these porphyrins. It was found that these compounds e...

2014
Darinka Dzubiel Heiko Ihmels Mohamed M A Mahmoud Laura Thomas

The interactions of the ILPR sequence (ILPR = "insulin-linked polymorphic region") a2 [d(ACAG4TGTG4ACAG4TGTG4)] with [2.2.2]heptamethinecyanine derivatives 1a-e and with the already established quadruplex ligands coralyne (2), 3,3'-[2,6-pyridinediylbis(carbonylimino)]bis[1-methylquinolinium] (3), 4,4',4'',4'''-(21H,23H-porphine-5,10,15,20-tetrayl)tetrakis[1-methylpyridinium] (4), naphtho[2,1-b:...

2006
Newton M. Barbosa Neto Samuel L. Oliveira Ilde Guedes Luis R. Dinelli Lino Misoguti Cleber R. Mendonça Alzir A. Batista Sergio C. Zílio

Modificações no sinal de absorção de estado excitado da 5,10,15,20-tetra(4-piridil)-21H,23Hporfirina, provocadas tanto pela substituição do íon central quanto pela adição de grupos periféricos, são investigadas empregando-se pulsos laser de 5 ns com 532 nm, juntamente com medidas de absorção linear e tempo de decaimento da fluorescência. A absorção saturada reversa (RSA) aumenta consideravelmen...

2011
P. Štěpánek P. Bouř

Magnetic circular dichroism (MCD) spectroscopy provides extended information about molecular electronic structure and transitions. Because the chirality is induced by static magnetic field it can also be used for non-chiral compounds. However, interpretation of the spectra is difficult, and precise computations using quantum mechanical approaches were implemented in publicly available software ...

نمودار تعداد نتایج جستجو در هر سال

با کلیک روی نمودار نتایج را به سال انتشار فیلتر کنید